I have a 1971 142E and all of the part required to keep it running (or get it running) are readily available. Unfortunately, some of the parts are only available from the European vendors so shipping can be a touch costly.
I am guessing that Jacksonville means one of the Jacksonvilles in the US (more than one!). If that is the case give Rock Auto a try first. Lots of the common 140 mechanical parts available there at a very low price. Other US based vendors include:
http://hiperformanceautoservice.com/
https://www.irollmotors.com/
http://212.247.61.152/us/main.aspx?guest=yes (VP Autoparts US division)
IROLL is more of an 1800 specialist; but, has parts for the 140 drivetrain. VP has a huge range of parts including interior parts / upholstery. There are other US based vendors; but, I have not dealt with them. There is also IPD USA who used to stock a wide range of vintage Volvo parts; but, now just sells a very limited range of parts.
In Europe there are:
https://www.cvi-automotive.se/en (CVI)
https://classic-volvo.com/ (Scandcar)
https://www.skandix.de/en/ (Skandix)
https://www.gcp.se/en/ (Volvo genuine classic parts)
There is also Nordicar; but, I have never ordered from them. Between CVI, Scandcar, Skandix and VP you can get any mechanical part that you need to keep the car running and you should be able to get a lot of the body and interior pieces you need for restoration although body and interior pieces unique to the 145 (as opposed to 142 or 144) may be a little harder to find or be unavailable. For those parts your need to do the EBay scrounge.
If you are prepared to pay, you can play!